This is easy with DeeZy now, it uses TrueHDD.
deezy.exe encode atmos --atmos-mode streaming movie.mkv and boom, you have converted your TrueHD Atmos track in your movie.mkv to a separate DDP+Atmos track (.ec3). I’ll likely vibe up a script that processes all TrueHD content in my library like that.
Unfortunately, Infuse doesn’t support external audio tracks for Jellyfin libraries, unlike Jellyfin, yet. Remuxxing every Atmos file is such a massive PITA that it’s stupid. Hopefully people can comment and upvote their support for external audio files, so we can get Atmos working in Infuse for all our Atmos content.